Study of CarbonT Hydrogen and Nitrogen Determination by Combustion-Gas Chromatography

The method for carbon-hydrogen-nitrogen determination based on dynamic rapid combustion of the sample, gas chromatographic sep-aration and thermalconductivity measurement of the gases N2,CO2 and H2O is critically considered and improved .In order to achieve instantan-cous combustion of all types of organic compounds , oxidizable metallic containers are used for the sample and dropped in the hot combustion zone while the carrier gas is momentarily enriched with pure oxygen .Flash combustion of the sample is followed by catalytic oxidation on a newly developed active catalyst .This reagent, adsorption-free and thermally resistant ,consist of pure chromic oxide, mechanically compressed and granulated .Copper treated with silver is used as reducing reagent .Unwanted gases are eliminated with Co3O4 containing silver ,and by utilizing the chemiadsorption properties of the column packing .Measurements are made by integrating and printing the electrical signal .The analytical process is controlled by means of a potentiometric recorder .The increased combustion capacity ,the practical absence of blanks and the very extended linearity of response of the detector make possible CHN determination in sample sizes of 0.1-3 mg .Except for sample weighing and calculation of results from the printed integration values ,all the operations are automatically controlled by a preset program.